SILVER LAKE RESEARCH NATURAL AREA
Supplement No. 15 1
Sarah E. Greene 2
Robin Lesher
Robert Wasem
The Research Natural Area described in this
supplement is administered by the National Park
Service, an agency of the U.S. Department of
the Interior. Research Natural Areas located
within National Parks or National Monuments
are administered by the Superintendent of the
Park or Monument. A scientist wishing to use
one of the tracts should contact the Superintendent responsible and outline the proposed
research.
Because of long involvement with scientific
and educational use of National Parks and
Monuments, the National Park Service has developed standard procedures regarding applications to use areas for research. A study proposal
must be prepared by the principal investigators
and approved by the Superintendent. Park Service research biologists will assist in preparing
proposals. Collecting permits are necessary.
There may be limitations on research activities.
The Research Natural Area described in this
supplement is part of a Federal system of such
tracts established for research and educational
purposes. Each Research Natural Area constitutes a site where natural features are preserved
for scientific purposes and natural processes are
allowed to dominate. Their main purposes are to
provide:
1. Baseline areas against which effects of
human activities can be measured;
1
Supplement No. 15 to "Federal Research Natural Areas in
Oregon and Washington: A Guidebook for Scientists and
Educators," by .Jerry F. Franklin, Frederick C. Hall. C. T.
Dyrness, and Chris Maser (U.S. Department of Agriculture, Forest
Service. Pacific Northwest Forest and Range Experiment Station,
498 p., illus .. 1972). The guidebook is available from the
Superintendent of Documents, U.S. Government Printing Office.
Washington. D.C. 20402: stock number 001-001-00225-9.
2
Sarah E. Greene is a research forester, Forestry Sciences
Laboratory, USDA Forest Service, Pacific Northwest Forest and
Range Experiment Station, Corvallis, Oregon. Robin Lesher is a
botanist in Bellingham, Washington. Robert Wasem is Park
Biologist, North Cascades National Park, Sedro Woolley,
Washington.
1984
2. Sites for study of natural processes in undisturbed ecosystems; and
3. Gene pool preserves for all types of organisms, especially rare and endangered
types.
The Federal system is outlined in "A Directory of the Research Natural Areas on Federal
Lands of the United States of America." 3
Of the 71 Federal Research Natural Areas established in Oregon and Washington, 45 are
described in "Federal Research Natural Areas in
Oregon and Washington: A Guidebook for
Scientists and Educators" (see footnote 1). Supplements to the Guidebook describe additions to
the system.
The guiding principle in management of Research Natural Areas is to prevent unnatural
encroachments or activities that directly or indirectly modify ecological processes. Logging
and uncontrolled grazing are not allowed, for
example, nor is public use that might impair scientific or educational values. Management
practices necessary for maintenance of ecosystems may be allowed.
Federal Research Natural Areas provide a
unique system of publicly owned and protected
examples of undisturbed ecosystems where scientists can conduct research with minimal
interference and reasonable assurance that investments in long-term studies will not be lost to
logging, land development, or similar activities.
In return, a scientist wishing to use a Research
Natural Area is obligated to:
1. Obtain permission from the appropriate administering agency before using the area; 4
3
Federal Committee on Ecological Reserves. A directory of
the Research Natural Areas on Federal lands of the United
States of America. Washington, D.C.: U.S. Department of
Agriculture, Forest Service; 1977.
4
Six agencies cooperate in this program in the Pacific
Northwest: U.S. Department of Agriculture-Forest Service;
U.S. Department of the Interior-Bureau of Land
Management, Fish and Wildlife Service, and National Park
Service; U.S. Department of Energy, and U.S. Department of
Defense.
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2. Abide by the administering agency's regulations governing use, including specific limitations on the type of research, sampling
methods, and other procedures; and
3. Inform the administering agency on progress
of the research, published results, and
disposition of collected materials.
The purpose of these limitations is to:
1. Insure that the scientific and educational
values of the tract are not impaired;
2. Accumulate a documented body of knowledge about the tract; and
3. Avoid conflict between studies.
Research must be essentially nondestructive;
destructive analysis of vegetation is generally
not allowed, nor are studies requiring extensive
modification of the forest floor or extensive excavation of soil. Collection of plant and animal
specimens should be restricted to the minimum
necessary to provide voucher specimens and
other research needs. Under no circumstances
may collecting significantly reduce population
levels of species. Collecting must also be carried
out in accordance with applicable State and
Federal agency regulations. Within these broad
guidelines, appropriate uses of Research Natural
Areas are determined by the administering
agency.
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1984
SILVER LAKE RESEARCH NATURAL AREA
An alpine lake surrounded by glaciers, with alpine plant communities and a rapidly flowing
stream.
4.
Silver Lake Research Natural Area (RNA)
was established in March 1974 to exemplify an
alpine cirque lake typical of those on the western
slopes of the North Cascades in Washington.
The 682.7-ha (l,687-acre) area includes twelve
glaciers, the summit of Mount Spickard, alpine
plant communities, a fastflowing outlet stream,
and a lake with an approximate maximum depth
of 159 m (525 ft). Elevations range from 2 720
m (8,979 ft) at the summit of Mount Spickard to
1125 m (3,712 ft) below the lake (fig. 1).
1984
Silver Lake RNA is in the northeast corner of
North Cascades National Park, Whatcom
County, Washington, 1 kilometer south of the
Canadian border. It is located in portions of
sections 2, 3, 4, T. 40 N., R. 12 E., and portions
of sections 34 and 35, T. 41 N., R. 12 E., Willamette meridian (lat. 48°59'05" N., long.
121°13'45" W.). It is bounded on the south by
Mount Spickard and on the north by Custer
Ridge.
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Access and Accommodations
Silver Lake RNA is accessible by helicopter
or by an arduous 2- to 3-day cross-country hike.
There are no trails. Anyone planning to enter the
area should notify Park Service headquarters at
Sedro Woolley, Washington. The nearest
commercial accommodations are at the Diablo
Lake Resort, 48 km (30 mi) east of Marblemount
on State Highway 20 (fig. 2).
Environment
Silver Lake occupies a cirque basin which was
subjected to extended periods of ice-scouring of
bedrock during the Pleistocene glaciations and
post-Pleistocene neoglaciation (fig. 3). The lake
is fed by the large glacier on the north slope of
Mount Spickard. There are twelve active glaciers
covering 320 ha (800 acres) in the Research
Natural Area. The one on the north slope of
Mount Spickard is the largest. It covers 0.9 km2
(0.6 mi2) and is 1.8 km (1.1 mi) long. It is
moderately crevassed and is retreating slightly.
The other glaciers are smaller cirque glaciers
ranging from 0.2 to 0.5 km (0.1 to 0.3 mi) in
width and 0.3 to 0.8 km (0.2 - 0.5 mi) in length
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1984
and varying in number of crevasses. All glaciers
are stationary, and the source of snow and ice
accumulation is direct snowfall and minor
snowdrift (Post and others 1971).
Silver Lake is unusually deep for a lake with
such a small surface area-0.16 km2 (0.26 mi2).
Table 1 shows how it compares with other lakes
in the United States. The continental ice sheet
around Silver Lake may have reached up to 2121
m (7,000 feet) in this area, but around Silver
Lake alpine glaciers were more prominent. The
extreme depth of Silver Lake is the result of
extensive, erosive action by these alpine
glaciers.
P
P
P
P
Daly (1912) mapped the area around Silver
Lake in 1904 and 1905, but the lake was not
shown on the map he published in 1912. Ice is
shown extending into the area now occupied by
the northeast end of the present lake. A
1:62,500-scale topographic map published by the
U.s. Geological Survey in 1913 shows Silver
Lake (then known as Glacier Lake) with about
one third of its present surface covered by the
Mount Spickard Glacier.
Aquatic Features
Silver Lake covers 65 ha (162.5 acres) and
reaches a depth of 159 m (520 ft). At 2 065-m
(6,763-ft) elevation, it is one of the highest lakes
in the North Cascades National Park. The lake is
classified as glacial because the glacial flour
held in suspension frequently restricts visibility,
as measured by the Secchi disk, to less than 4 m
(13.2 ft). The water is extremely oligotrophic
and has low values of specific conductance,
bicarbonate alkalinity, and hardness, with
slightly acid pH values (table 2). Most of the
lake is homothermous, with no well-defined
thermal layers of epilimnion, metalimnion
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(thermocline), and hypolimnion (fig. 4). Water
temperature at the surface, near the outlet
stream, measured 8.3°C (46.9°F) at 0945 P.d.t.
on August 21, 1979, and 4.5°C (40.1°F) at 30 m
(99 ft). The temperature at maximum depth was
estimated to be 4.0°C (39.2°F).
Both the inlet and outlet streams flow across
rock and gravel. The inlet stream on the southwest side of the lake comes from the large
Mount Spickard glacier and contains substantial
sedimentary deposits up to 70 m (231 ft) in
width. Water temperature at the inlet measured
1.7°C (35°F) at 1630 P.d.t. on August 21, 1979.
The outlet stream contains rough cobbles of
fairly uniform size which do not extend into the
lake. Except for sporadic sedges, there is very
little riparian vegetation along either the inlet or
the outlet.
1984
Biota
Most of the vegetation of Silver Lake RNA
falls into the Alpine Zone of Franklin and Dyrness (1973), a zone of limited extent in the
mountains of Washington and Oregon. The
structure and composition of the plant associations at Silver Lake are determined by the basic
features of alpine regions in the temperate zonewind in relation to topography, snow accumulation, and time of snow melt, all in combination with various edaphic features. A survey of
the plants in the lake basin, inlet, east rim, and
lower nothern cirque walls, up to 2 320 m (7,656
ft) was conducted August 12-14, 1980. The
survey also included the eastern slope ofthe
outlet stream down into the Subalpine Zone
(Franklin and Dyrness 1973) at 1 830 m (6,039
ft). Extensive cliffs, glaciers, and steep talus
slopes prevented access to the south rim.
The lake basin is characterized by steep and
unstable talus slopes, cliffs, rock outcrops,
glaciers, and permanent snowfields. Generally
the entire basin has poor soil development. The
vegetation and habitats have been described for
seven locations in the RNA (fig. 1). Vegetation
is sparse; plants cannot become established in
areas where erosion, rock slides, and avalanches
frequently occur. Plants have colonized sites
where the substrate is somewhat stable and soil
and moisture are available.
A delta of glacial silt and scree surrounds the
inlet to Silver Lake (Location 1, fig. 1). Vegetation occurs around this inlet in moist areas protected from the outwash. Graminoids dominate
the area: Festuca ouina var. breuifolia, Trisetum
spicatum, Poa alpina, and Juncus mertensianus.5
The rare Saxifraga debilis is found adjacent to the
inlet stream (Washington Natural Heritage
Program 1982).
Above the northwest shore of the lake are
steep talus slopes, extending to 2350 m (7,755 ft),
which are often covered with snow at higher
elevations (Location 2, fig. 1). Vegetation is
sparse. The slopes are broken by large rock outcrops. The bluffs of these outcrops support mats
of Salix cascadensis, Phyllodoce glanduliflora, and
sometimes Cassiope tetragona var. saximontana. At
the base of these outcrops, where snowmelt
occurs late in the season, Carex spectabilis, C.
nigricans, Phyllodoce glanduliflora, various
graminoids, and herbs occur. On the talus itself
vegetation is found around seepages and streams.
Epilobium latifolium is common in sites of
ephemeral seepage. The rocky plateaus support
lush meadows of Potentilla fruticosa. On the more
gentle slopes with later snowmelt a community
dominated by Phyllodoce glanduliflora occurs
Steep slopes and cliffs characterize the eastern
section of the north rim of the lake (Location 3,
fig. 1). Only the rock ledges along the lake where
occasional herbaceous perennials occur were
surveyed. Vegetation of the higher cliffs,
primarily in seepage sites, was presumably
dominated by Phyllodoce glandulifiora. Krummholz clumps appeared on the occasional stable
substrate where moisture is retained.
The south-facing talus slopes (Location 4, fig.
1) above the east rim of Silver Lake extend from
2130 to 2230 m (7,029 to 7,359 ft). Vegetation is
found primarily in sites protected from avalanching and erosion, where soil and water accumulate. Vegetation mats on these areas are
composed of Potentilla fruticosa, Carex spectabilis,
Salix niualis, Silene acaulis, graminoids
and herbaceous perennials.
5 Scientific names of vascular plants and authors are listed in
table 3.
1984
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A bench along the east rim north of the outlet,
about 30 m (100 ft) above the lake (Location 5,
fig. l), is primarily a fell-field with boulders (fig.
5). An extensive boulder field covers the west
slope down to the lake shore. Sprawling, lowgrowing shrubs inhabit the fell-field: Juniperus
communis, Arctostaphylos uva-ursi, Penstemon
davidsonii, and Potentilla fruticosa. Pinus
albicaulis, Abies lasiocarpa and Picea engelmannii
grow in krummholz clumps along the east flank
of the bench. Lichens grow on the rocks.
Vegetation along the east rim south of the
outlet stream is sparse (Location 6, fig. 2). The
area is characterized by a bench of fell-fields and
boulder fields, barren talus slopes to the east,
and terraced cliffs on the west slope down to the
lake shore. Empetrum nigrum is the dominant
shrub found in rocky, exposed sites. Salix nivalis
forms vegetative mats in rockier and more
exposed sites than those inhabited by Empetrum
nigrum. Various heather communities occur in
the more protected sites with accumulated soil.
The east-facing slope north of the outlet
stream is barren, with only a few refuge areas for
plants (Location 7, fig. 1). Heather communities
grow on sites of higher ground and better
drainage (fig. 6). Sedge meadows of Carex
spectabilis and/or C. nigricans occur where
snowmelt is late. Seepage areas at higher elevations are dominated by lush carpets of moss,
Saxifraga tolmiei, and Luzula piperi. Abies
lasiocarpa, growing as krummholz, occupies
steeper parts of the slope in well drained sites
(fig. 7).
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1984
Maps and Aerial Photographs
Special maps applicable to the natural area
include: TOPOGRAPHIC-Mount Spickard,
Washington, 7.5' quadrangle, scale 1:24,000 issued by U.S. Geological Survey in 1969; Mount
Challenger, Washington, 15' quadrangle, scale
1:62,500, issued by U.S. Geological Survey in
1953; North Cascades National Park Map, scale
1:100,000, issued by U.S. Geological Survey in
1974; GEOLOGIC-map of Washington, scale
1:500,000 (Huntting and others 1961); and International Boundary from the Gulf of Georgia
to the Northwesternmost point of the Lake of
the Woods, Sheet 5, (Daly 1912). The Superintendent of North Cascades National Park (Sedro
Woolley, Washington) can provide details on
the most recent aerial photo coverage for the
area.
History of Disturbance
There is no evidence of fire in the natural
area. Because of high elevation and lack of
fuels, fire is unimportant as a natural disturbance. Glaciation has provided the most significant disturbance. Snow and rock avalanches
occur periodically. There is little sign of disturbance by either wild animals or humans. Current
natural disturbances include rock and snow
avalanching.
Research
Depth soundings and tests for water quality of
Silver Lake are given in table 2 and figure 1.
Results of a floral survey of the RNA are given
in table 3. This RNA provides very good opportunities for additional research in alpine plant
communities and works of glaciers.
1984
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1984
Literature Cited
Bue, C. D.
Principal lakes of the United States. Geological
Survey Circular 476. U.S. Department of the Interior, U.S. Geological Survey. Washington D.C.:
1963. 22 p.
Daly, R. E.
Geology of the North American Cordillera at the
forty-ninth parallel. Memoir No. 38, Part I. Map
88A. Ottawa, Canada: Geological Survey of Canada,
1912.
Franklin, Jerry F. and Dyrness, C. T.
Natural vegetation of Oregon and Washington . Gen.
Tech. Rep. PNW-8. Portland, OR: U.S. Department
of Agriculture, Forest Service, Pacific Northwest
Forest and Range Experiment Station. 1973.417 p.
Hitchcock, C.; Cronquist, A.; Ownbey, M.; and
Thompson, J. W.
Vascular plants of the Pacific Northwest: 5 Volumes. Seattle, WA; University of Washington Press;
1955-69.
Huntting, Marshall T.; Bennett, W.A.G.; Livingston
Jr., Vaughan E.; and Moen, Wayne S.
Geologic map of Washington. Olympia, WA:
Washington Department of Natural Resources,
Division of Geology and Earth Resource. 1961.
Post, Austin; Richardson, Don; Tangfour, Wendell V.;
Rosselot, F. L.
Inventory of glaciers in North Cascades,
Washington. Prof. Paper 705-A. Washington, D.C.:
Department of the Interior, U.S. Geological Survey.
1971. 26 p.
Washington Natural Heritage Program.
Endangered, threatened, and sensitive vascular
plants of Washington. Olympia, W A: Department
of Natural Resources. 1982.25 p.
1984
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